Location: Cool and Cold Water Aquaculture Research
Project Number: 8082-32000-006-03-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Jan 15, 2012
End Date: Jan 14, 2017
Selective breeding for increased disease resistance is a powerful tool to complement animal health control strategies in the prevention of devastating disease. Through selective breeding over 3 generations, we (NCCCWA) have increased resistance to the bacterial cold water disease agent, Flavobacterium psychrophilum in RBT. Preliminary field testing indicates superior survival and on-farm performance with this selected RBT stock at sites experiencing endemic disease. Interestingly, this selection has also resulted in a significant increase in spleen size and alterations of the in vitro immune response profiles among the resistant fish. Thus, the overall impact of this selective breeding may have also significantly affected both innate and adaptive immune functions.
Our approach utilizes pedigreed rainbow trout lines, bred for differences in survival following laboratory challenge with the Fp strain, CSF259-93. This selection process has also led to increased spleen size in resistant fish and unique leukocyte response profiles to in vitro challenge with Fp LPS. The first objective will employ a panel of genome-sequenced Fp strains and other Gram-negative salmonid pathogens to probe the specificity of the induced resistance. Our extensive genomic analysis of Fp virulence variants will facilitate characterization of potential broad-based resistance. The second objective will dissect the cellular and molecular bases of this genetic resistance. Differential effects on cytokine and antibody production in critical immune tissues, including the spleen, will be determined. The third objective will address the impact of this selective breeding on immunoprophylaxis elicited by vaccination with homologous and heterologous Fp strains, as well as other bacterial pathogens.